The present invention relates to a process for producing fibrous mats as a starting material for compression moulded articles, in that fiberized materials, preferably waste materials, are mixed with thermoplastic and/or duroplastic binders, the mixture is spread to form a first fleece layer, on which is placed a fabric, e.g. a polyester fabric, with a heat-activatable finish having an affinity for the fibre binder, then a further fleece layer is spread thereon and the thus formed composite or sandwich fleece is compressed accompanied by the thermal activation of the binder and the finish to form a mat, from which it is possible to produce moulded articles by compression moulding at elevated temperatures.
A process and an apparatus for performing the same forms the subject matter of the earlier-dated U.S. patent application of the present inventor (Ser. No. 697,452). Whereas single fibrous mats (e.g. according to DE-OS 28 45 112) are relatively sensitive during transportation and storage as a result of their limited inherent stability and consequently can only be stored and transported in stacked blanks, the fabric gives the mat an increased stability and flexibility in the aforementioned process, so that it can e.g. be rolled up and can be removed from the reel for the purpose of producing the compression moulded articles. The further decisive advantage of such composite fleeces made from fibrous fleece or non-woven fabric layers with an incorporated fabric is that the tensile strength is considerably increased, so that even in the case of moulded articles with low contours, the compression moulding thereof can take place in a single operation and no preshaping is required, as is the case with single fibrous fleeces.
The fabric used in the said process, preferably a polyester fabric must on the one hand have a slip-resistant finish and on the other hand the finish must be chosen in such a way that it has no negative effects on the mat and/or moulded article during the thermal processes (heat activation of the binder during mat production and curing of the binder during moulding to give the moulded article). Thus, the finish is preferably formed from a material having an affinity to the binders for the fibres, e.g. synthetic resins, such as phenolic resins and the like. It is disadvantageous that fabrics finished in this way are only commercially available in specific qualities and types, which are generally not specifically matched to the production of fibrous mats and/or compression moulded articles. This applies not only with regards to the composition, but e.g. also with regards to the weight per unit area of the finish. Finally, such completely finished fabrics are relatively expensive.